testing

# Testing Skill Write effective, meaningful Flutter and Dart tests that catch real regressions. ## When to Use Use this skill when: * Writing unit tests for business logic, repositories, or utility classes. * Writing widget tests for UI components. * Reviewing existing tests for correctness and coverage. * Fixing flaky or false-positive tests. * Deciding between unit tests, widget tests, and integration tests. --- ## 1. Test Validity Before writing or accepting a test, ask: > **"Can this test actually fail if the real code is broken?"** - Avoid tests that only confirm mocked/fake behavior without exercising real logic. - Avoid tests that confirm behavior guaranteed by the language or standard library. - Every test must be capable of catching a real regression. ```dart // BAD — tests the mock, not real logic test('should return user', () { when(() => repo.getUser()).thenReturn(fakeUser); expect(repo.getUser(), fakeUser); // Only proves the mock works }); // GOOD — tests the cubit's state transitions driven by the mock blocTest<UserCubit, UserState>( 'should emit loaded state when getUser succeeds', build: () { when(() => repo.getUser()).thenAnswer((_) async => fakeUser); return UserCubit(repo); }, act: (cubit) => cubit.fetchUser(), expect: () => [ const UserState(status: UserStatus.loading), UserState(status: UserStatus.loaded, user: fakeUser), ], ); ``` --- ## 2. Structure Always use `group()` in test files. Name the group after t...